Enhanced photocatalytic activity of g-C3N4 modified BiOBr for the degradation of reactive blue 19 under visible light

Abstract

Nowadays, the concentration of dyes in water is elevated as a consequence of unregulated disposal, which leads to water contamination. To mitigate their detrimental effects, effective elimination is crucial. In this regard, g-C₃N₄/BiOBr was synthesised via a hydrothermal technique to examine the visible light-driven photocatalytic decomposition of reactive blue 19 (RB19). The synthesised catalyst was characterised using multiple techniques, such as diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) spectroscopy. The degradation efficiency of 10 wt% g-C₃N₄-loaded BiOBr towards RB19 in the presence of visible light was observed to be 89% within 240 min under visible light. Moreover, control experiments validate the involvement of superoxide anions (O₂˙⁻), hydroxyl radicals (˙OH), and holes (h⁺) in the photocatalytic degradation pathway. The calculated band positions support the formation of Z-scheme-type heterojunctions. In addition, the high-resolution mass spectrometry (HR-MS) analysis confirms the existence of small fragments (m/z = 184, 202, etc.), hence validating the photodegradation process. Moreover, the synthesised catalyst demonstrates remarkable stability and reusability. Moreover, the photocatalytic degradation efficiency in different water samples, including deionised water, RO water, and tap water, was found to be practically similar. Consequently, the photocatalyst can effectively eliminate the harmful pollutants present in wastewater.